CVE-2022-34029 in NJS
Summary
by MITRE • 07/19/2022
Nginx NJS v0.7.4 was discovered to contain an out-of-bounds read via njs_scope_value at njs_scope.h.
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Analysis
by VulDB Data Team • 08/06/2022
The vulnerability identified as CVE-2022-34029 affects Nginx NJS version 0.7.4 and represents a critical out-of-bounds read condition within the njs_scope_value function located in njs_scope.h. This flaw occurs during the processing of JavaScript code within the Nginx server environment, specifically when handling scope values during script execution. The issue stems from insufficient bounds checking in the JavaScript engine's scope management system, which allows an attacker to potentially read memory locations beyond the intended boundaries of allocated buffers.
The technical implementation of this vulnerability involves the njs_scope_value function failing to validate array indices or memory offsets when accessing scope-related data structures. When Nginx processes JavaScript code through its NJS module, the engine attempts to retrieve values from scope arrays without proper boundary validation, creating an opportunity for attackers to manipulate input data to trigger memory access violations. This type of vulnerability falls under the CWE-129 weakness category, specifically addressing inadequate bounds checking in array indexing operations. The out-of-bounds read can potentially expose sensitive memory contents including stack data, heap information, or other internal structures that may contain credentials, configuration details, or application state information.
From an operational perspective, this vulnerability presents significant risks to Nginx deployments that utilize the NJS module for server-side JavaScript processing. Attackers could leverage this flaw to extract information from the server's memory space, potentially leading to information disclosure attacks that might reveal system internals, user credentials, or application data. The impact extends beyond simple information leakage as the out-of-bounds read could serve as a precursor to more severe exploits such as code execution or privilege escalation. The vulnerability affects systems where Nginx is configured to process JavaScript code through its NJS module, which includes various web applications, API gateways, and reverse proxy configurations that rely on server-side JavaScript processing capabilities.
The mitigation strategy for CVE-2022-34029 involves immediate patching of Nginx installations to versions that address the out-of-bounds read condition in the NJS module. Organizations should prioritize updating their Nginx deployments to the latest stable releases that contain fixes for this vulnerability. Additionally, system administrators should implement monitoring to detect unusual memory access patterns or potential exploitation attempts. Security teams should also consider implementing network segmentation and access controls to limit exposure of systems running Nginx with NJS functionality. The vulnerability demonstrates the importance of proper memory management in interpreted languages within web server contexts and aligns with ATT&CK techniques related to information gathering and privilege escalation through memory corruption vulnerabilities. Regular security assessments and vulnerability scanning should be conducted to identify other potential weaknesses in JavaScript processing modules and ensure comprehensive protection against similar out-of-bounds access issues.